CN111529410B

CN111529410B - Dental material with improved setting properties

Info

Publication number: CN111529410B
Application number: CN201911265001.8A
Authority: CN
Inventors: N·莫斯奈尔; A·吉安斯米迪斯; M·韦斯特法尔; A·布罗特; B·格瑞本巴尔
Original assignee: Ivoclar Vivadent AG
Current assignee: Ivoclar Vivadent AG
Priority date: 2019-02-07
Filing date: 2019-12-11
Publication date: 2022-10-21
Anticipated expiration: 2039-12-11
Also published as: ES2918149T3; EP3692975B1; CN111529410A; US20200253838A1; EP3692975A1; US11141356B2

Abstract

Dental materials having improved setting properties. A radically polymerizable dental material comprising a combination of a thiourea derivative, a hydroperoxide and at least one peroxide as an initiator system for the radical polymerization.

Description

Dental material with improved setting properties

Technical Field

The present invention relates to radically polymerizable compositions with improved setting properties, which are particularly suitable as dental materials, for example as prosthetic materials, cements, adhesives and composite materials for direct filling. The composition comprises a redox system comprising a hydroperoxide, a thiourea derivative and a peroxide as an initiator for the free radical polymerization.

Background

The main fields of use of polymers in the dental field are mobile prostheses (for example teeth and prosthetic base materials) and fixed prostheses (for example facing materials, crowns or cements), filling materials (for example direct or indirect filling of composites, fixed cements or adhesives) or auxiliary materials (for example impression materials). The polymers are generally obtained by free radical polymerization of a suitable composition comprising a polymerizable organic matrix, typically a mixture of monomers, initiator components and stabilizers.

Methyl Methacrylate (MMA) is generally used as monomer (for prosthetic materials), functionalized monomers such as 2-hydroxyethyl methacrylate (HEMA) or mixtures of acid group-containing binder monomers such as 10-Methacryloyloxydecyl Dihydrogen Phosphate (MDP) with dimethacrylate (for adhesives), or mixtures containing only dimethacrylate (for composite cements and filled composites). Frequently used dimethacrylates are 2,2-bis [4- (2-hydroxy-3-methacryloxypropyl) phenyl ] propane (bis-GMA) and 1,6-bis- [ 2-methacryloxyethoxycarbonylamino ] -2,4,4-trimethylhexane (UDMA), which have high viscosities and give polymers with very good mechanical properties. Most importantly, triethylene glycol dimethacrylate (TEGDMA), 1,10-decanediol dimethacrylate (D3 MA) or bis- (3-methacryloxymethyl) tricyclo- [5.2.1.02,6] Decane (DCP) were used as reactive diluents.

Methacrylate-based dental materials are cured by free radical polymerization, wherein, depending on the field of use, free radical photoinitiators (photocuring, direct filling composites and adhesives), thermal initiators (indirect composites or prosthetic materials) or redox initiator systems (composite cements) are used. Combinations of photoinitiators with redox initiators are also known, for example, when filling deep cavities.

Redox systems are used first when there is a risk of incomplete curing, for example in the case of prosthetic materials, due to low reactivity of the monomers or, in the case of fixed cements, due to insufficient radiation.

In order to ensure sufficient storage stability of the materials, materials based on redox initiators are generally used as so-called two-component systems (2C systems), in which an oxidizing agent (peroxide or hydroperoxide) and a reducing agent (amine, sulfinic acid, barbiturates, thiourea, etc.) are incorporated into two separate components. These components are mixed with each other shortly before use. The two components must be matched so that they can be easily homogeneously blended and used and so that sufficient processing time for dental use is obtained. The processing time refers to the time period between the blending of the two components and the onset of curing of the mixed material. It should be about 90 to 150s. On the other hand, the curing time, i.e. the time until the material has completely hardened, cannot be too long. A cure time of about 3 to 5 minutes is most preferred.

Redox initiator systems based on mixtures of dibenzoyl peroxide (DBPO) with tertiary aromatic amines such as N, N-diethanol-p-toluidine (DEPT), N-dimethyl-sym-xylidine (DMSX) or N, N-diethyl-3,5-di-tert-butylaniline (DABA) have long been used primarily for dental composite cements. Processing and curing times can be set relatively well using a DBPO/amine based redox initiator system, in combination with a phenolic inhibitor. A disadvantage of this DBPO/amine system is the discoloration caused by the slow oxidation of the amine. Furthermore, in the case of a redox initiator system based on DBPO/amine, the radical formation is impaired by the acid and thus also by the acid monomers usually used for the preparation of enamel-dentin adhesives. The amine component is protonated and thus deactivated by the acid-base reaction.

The above disadvantages can be partially overcome with hydroperoxide redox initiator systems, since tertiary amines are not required as reducing agents. Furthermore, hydroperoxides are more thermally stable than peroxides. Temperature T of cumene hydroperoxide with a half-life of, for example, 10 hours _1/2 Is 158 ℃; 10 hour half life temperature T of DBPO _1/2 Is only 73 deg.c.

DE 2635595C2 discloses polymerizable dental filling compounds comprising a substituted thiourea reducing agent and a hydroperoxide oxidizing agent in combination as an initiator system. These materials are said to have improved color stability, excellent cure rates, and improved storage stability.

EP 1693046B1 discloses dental cements and core build-up materials comprising (2-pyridyl) -2-thiourea derivatives in combination with a hydroperoxide, wherein the hydroperoxide group is bonded to a tertiary carbon atom.

WO 2007/016508A1 discloses a polymerizable dental composition comprising a thiourea derivative and a hydroperoxide in combination as an initiator system. The composition is free of monomers having acid groups.

According to EP 1754465B1, the cumene hydroperoxide/acetylthiourea system has unusable slow curing kinetics. It is suggested to add soluble copper compounds to overcome this problem. Copper ions are colored and can affect the color of the material.

US 7,275,932B2 proposes the use of hydroperoxides and thiourea derivatives in combination with acid compounds as accelerators. Preferred acid compounds are acrylates and methacrylates having acid groups such as methacrylic acid.

EP 2233544A1 and EP 2258336A1 disclose dental materials comprising hydroperoxide and thiourea derivatives in combination with vanadium compounds as accelerators. Vanadium compounds can cause green discoloration of the material.

To avoid the disadvantages associated with organic peroxides and tertiary amines, US 6,815,470B2 proposes the use of aryl borates in combination with acid compounds and peroxides as initiator systems. Aryl borates are said to form aryl boranes by reaction with acid compounds, which liberate polymerizable free radicals when reacted with oxygen. Polymerizable monomers having an acid group may be used as the acid compound.

Despite the many efforts made to overcome the disadvantages associated with peroxide and amine accelerators, no initiator system has been found which is satisfactory in every respect for dental use.

Disclosure of Invention

It is an object of the present invention to provide a dental material which does not have the disadvantages of the prior art. These materials will on the one hand have a high storage stability and show no discoloration, but at the same time harden rapidly and still have a processing time suitable for dental use.

This object is achieved by a radically polymerizable dental material comprising a combination of a thiourea derivative and a hydroperoxide and additionally at least one peroxide as an initiator system for the radical polymerization. According to the present invention, it has surprisingly been found that the reactivity of initiator systems based on hydroperoxides and thiourea derivatives can be accelerated considerably by adding small amounts of peroxides.

Preferred hydroperoxides according to the invention are those of the formula R- (OOH) _n Wherein R is an aliphatic or aromatic hydrocarbon group and n is 1 or 2. Preferred radicals R are alkyl radicals and aryl radicals. The alkyl group may be linear, branched or cyclic. The cyclic alkyl group may be substituted with an aliphatic alkyl group. Alkyl groups having 4 to 10 carbon atoms are preferred. The aryl group may be unsubstituted or substituted with an alkyl group. Preferred aromatic hydrocarbon radicals are substituted by 1 or 2 alkyl radicalsA phenyl group of (a). The aromatic hydrocarbon group preferably contains 6 to 12 carbon atoms. Particularly preferred hydroperoxides are tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butyl hydroperoxide, tert-hexyl hydroperoxide, 2,5-dimethyl-2,5-di (hydroperoxy) hexane, diisopropylbenzene monohydroperoxide, p-xylene

Alkyl hydroperoxide, p-isopropyl cumene hydroperoxide and mixtures thereof. Very particular preference is given to Cumene Hydroperoxide (CHP).

Preferred peroxides according to the invention are those of the formula R '- (O-O-R') _m Wherein R 'and R' in each case represent an aliphatic or aromatic hydrocarbon radical or an acyl radical and m is 1 or 2. Diacyl peroxides are particularly preferred. Preferred aliphatic hydrocarbon groups are groups having 3 to 8 carbon atoms, preferred aromatic hydrocarbon groups are groups having 6 to 12 carbon atoms, of which phenyl groups substituted with 1 or 2 alkyl groups are particularly preferred. Preferred acyl groups are those containing from 2 to 20 carbon atoms.

Preferred peroxides in which R 'and R' in each case represent an aliphatic or aromatic hydrocarbon radical are α, α -bis (tert-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, tert-butyl cumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3.

Preferred diacyl peroxides are isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, m-toluoylbenzoyl peroxide, benzoyl peroxide (DBPO), and mixtures thereof. A very particularly preferred peroxide is benzoyl peroxide (DBPO). Hydroperoxides are not peroxides within the meaning of the present invention.

Preferred thiourea derivatives are the compounds listed in paragraph [0009] of EP 1754465A 1. Particularly preferred thiourea derivatives are acetylthiourea, allylthiourea, pyridylthiourea and phenylthiourea, hexanoylthiourea and mixtures thereof. Acetylthiourea (ATU) is very particularly preferred.

Further preferred are thiourea derivatives having the formula

Wherein

X is H or Y, and X is H or Y,

y is an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, a chloro-, hydroxy-or mercapto-substituted alkyl group having 1 to 8 carbon atoms, an alkenyl group having 3 to 4 carbon atoms, an aryl group having 6 to 8 carbon atoms, a chloro-, hydroxy-, methoxy-or sulfonyl-substituted phenyl group, an acyl group having 2 to 8 carbon atoms, a chloro-or methoxy-substituted acyl group, an aralkyl group having 7 to 8 carbon atoms, or a chloro-or methoxy-substituted aralkyl group, and

z is NH ₂ NHX or NX ₂ 。

The hydroperoxide is preferably used in an amount of 0.01 to 5.0% by weight, particularly preferably 0.05 to 4.0% by weight, and very particularly preferably 0.1 to 3.0% by weight. The thiourea derivative is preferably used in a molar amount of from 25 to 100mol%, preferably from 50 to 100mol%, relative to the molar amount of hydroperoxide, very particularly preferably in the same molar concentration as the hydroperoxide. The peroxide is preferably used in an amount of from 1 to 15% by weight, preferably from 1 to 10% by weight, very particularly preferably from 2 to 8% by weight, relative to the mass of hydroperoxide.

The initiator system according to the invention is particularly suitable for curing free-radically polymerizable compositions.

In addition to the initiator system, the composition according to the invention preferably comprises at least one free-radically polymerizable monomer. Compositions comprising at least one monofunctional (meth) acrylate or multifunctional (meth) acrylate as radically polymerizable monomer are particularly preferred. The monofunctional (meth) acrylate means a compound having one radical polymerizable group, and the polyfunctional (meth) acrylate means a compound having two or more, preferably 2 to 4 radical polymerizable groups. According to a very particularly preferred embodiment, the composition according to the invention comprises at least one dimethacrylate or a mixture of monomethacrylate and dimethacrylate. The material to be cured in the mouth preferably comprises monofunctional methacrylates and/or multifunctional methacrylates as radically polymerizable monomers.

Preferred monofunctional or polyfunctional (meth) acrylates are methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate or isobornyl (meth) acrylate, p-cumylphenoxyethylene glycol methacrylate (CMP-1E), 2- (2-biphenyloxy) ethyl methacrylate, bisphenol A dimethacrylate, bis-GMA (addition product of methacrylic acid and bisphenol A diglycidyl ether), ethoxylated or propoxylated bisphenol A dimethacrylate, for example 2- [4- (2-methacryloyloxyethoxyethoxy) phenyl-acrylate]-2- [4- (2-methacryloyloxyethoxy) phenyl]Propane) (SR-348 c, from Sartomer; containing 3 ethoxy groups) and 2,2-bis [4- (2-methacryloxypropoxy) phenyl]Propane, UDMA (addition product of 2-hydroxyethyl methacrylate and 2,2,4-trimethylhexamethylene-1,6-diisocyanate), V-380 (addition product of a mixture of 0.7mol of 2-hydroxyethyl methacrylate and 0.3mol of 2-hydroxypropyl methacrylate and 1mol of α, α, α ', α' -tetramethylmetaxylene diisocyanate), di-, tri-or tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate and glycerol dimethacrylate and glycerol trimethacrylate, 1,4-butanediol dimethacrylate, 1,10-decanediol dimethacrylate (D ₃ MA), bis (methacryloxymethyl) tricyclo- [5.2.1.02,6]Decane (DCP), polyethylene glycol dimethacrylate or polypropylene glycol dimethacrylate such as polyethylene glycol 200 dimethacrylate or polyethylene glycol 400 dimethacrylate (PEG 200DMA or PEG 400 DMA) or 1,12-dodecanediol dimethacrylate or combinations thereofAnd (3) mixing.

According to one embodiment, the composition according to the invention preferably additionally comprises one or more free-radically polymerizable monomers (binder monomers) containing acid groups, in addition to the abovementioned monomers. These impart self-adhesive and/or self-etching properties to the material. Thus, monomers containing acid groups are particularly suitable for the preparation of self-adhesive dental materials such as fixing cements.

Preferred acid group-containing monomers are polymerizable carboxylic acids, phosphonic acids and phosphoric esters and their anhydrides. Preferred carboxylic acids and carboxylic acid anhydrides are 4- (meth) acryloyloxyethyl trimellitic anhydride, 10-methacryloyloxydecyl malonic acid, N- (2-hydroxy-3-methacryloyloxypropyl) -N-phenylglycine, 4-vinylbenzoic acid. Preferred phosphates are 2-methacryloyloxyethylphenylphosphate, 10-Methacryloyloxydecylphosphate (MDP) and dipentaerythritol pentamethylacryloxyphosphate. Preferred phosphonic acids are 4-vinylbenzylphosphonic acid, 2- [4- (dihydroxyphosphoryl) -2-oxabutyl ] -acrylic acid and their amides, esters such as 2- [4- (dihydroxyphosphoryl) -2-oxabutyl ] -acrylic acid-2,4,6-trimethylphenyl ester.

Particularly preferred acid group-containing monomers are 4-vinylbenzylphosphonic acid, 2- [4- (dihydroxyphosphoryl) -2-oxetanyl ] -acrylic acid and their amides, esters such as 2- [4- (dihydroxyphosphoryl) -2-oxetanyl ] -acrylic acid-2,4,6-trimethylphenyl ester, (meth) acrylamide dihydrogen phosphate such as 6-methacrylamidohexyldihydrogen phosphate or 1,3-bis (methacrylamido) -propan-2-yl-dihydrogen phosphate, and mixtures thereof. These particularly preferred acid group-containing monomers are characterized by a high hydrolytic stability.

In addition to the initiator system according to the invention, the compositions according to the invention may advantageously additionally comprise an initiator for free-radical photopolymerization. Such compositions are dual-curing, i.e., they can be cured both chemically and by light. Preferred photoinitiators are benzophenone, benzoin and derivatives thereof, alpha-diketones and derivatives thereof such as 9,10-phenanthrenequinone, 1-phenylpropane-1,2-dione, butanedione and 4,4' -dichlorobenzil. Preference is given to using Camphorquinone (CQ) and 2,2-dimethoxy-2-phenyl-acetophenone in combination with an amine such as 4- (dimethylamino) -benzoic acid ethyl Ester (EDMAB) or N, N-dimethylaminoethyl methacrylate as reducing agent.

Amine-free compositions are preferred according to the invention. Accordingly, norrish type I photoinitiators are particularly preferred. The Norrish type I photoinitiator does not require an amine component.

Preferred Norrish type I photoinitiators are acyl or bisacylphosphine oxides. Monoacyltrialkygermanes, diacyldialkylgermanes and tetraacylgermane compounds, e.g. benzoyltrimethylgermane, dibenzoyldiethylgermane, bis (4-methoxybenzoyl) diethylgermane

Tetrabenzoylgermane and tetra (o-methylbenzoyl) germane are particularly preferred.

Furthermore, mixtures of different photoinitiators may also be used, for example bis (4-methoxybenzoyl) diethylgermane or tetrakis (o-methylbenzoyl) germane in combination with camphorquinone and ethyl 4-dimethylaminobenzoate.

Furthermore, the composition according to the invention may advantageously comprise one or more organic or inorganic fillers. Particulate fillers are preferred. The filler-containing compositions are particularly suitable as dental setting cements or filling compounds.

Preferred inorganic fillers are oxides such as SiO ₂ 、ZrO ₂ And TiO 2 ₂ Or SiO ₂ 、ZrO ₂ ZnO and/or TiO ₂ Mixed oxides, nanoparticles or ultrafine fillers such as fumed silica or precipitated silica, glass powders such as quartz, glass ceramics, borosilicate or radio-opaque glass powders, preferably barium or strontium aluminosilicate glass, and radio-opaque fillers such as ytterbium trifluoride, tantalum (V) oxide, barium sulfate or SiO ₂ Mixed oxides with ytterbium (III) oxide or tantalum (V) oxide. The dental material according to the invention may also comprise fibrous fillers, nanofibers, whiskers or mixtures thereof.

Preferably, the oxide has a particle size of 0.010 to 15 μm, the nanoparticles or ultrafine fillers have a particle size of 10 to 300nm, the glass powder has a particle size of 0.01 to 15 μm, preferably 0.2 to 1.5 μm, and the radiopaque fillers have a particle size of 0.2 to 5 μm.

Particularly preferred fillers are SiO with a particle size of 10 to 300nm ₂ And ZrO ₂ A glass powder having a particle size of 0.2 to 1.5 μm, in particular a radiopaque glass powder such as barium or strontium aluminosilicate glass, and a radiopaque filler having a particle size of 0.2 to 5 μm, in particular ytterbium trifluoride and/or SiO ₂ Mixed oxide with ytterbium (III) oxide.

In addition, ground prepolymers or pearl polymers (isofillers) are suitable as fillers. These may consist of organic polymers alone, or organic polymers which are themselves filled with inorganic fillers such as radiopaque glass frit(s) and ytterbium trifluoride. The monomers and fillers defined above are suitable for preparing milled prepolymers and pearl polymers. The compositions for producing complete dentures preferably comprise only organic fillers, particularly preferably ground polymers based on polymethyl methacrylate (PMMA) or pearl polymers, very particularly preferably pearl polymers based on PMMA, as fillers.

All particle sizes are weight average particle sizes unless otherwise stated, wherein particle size determination of 0.1 μm to 1000 μm is performed by static light scattering, preferably using a LA-960 static laser scattering particle size analyzer (Horiba, japan). Here, a laser diode having a wavelength of 655nm and an LED having a wavelength of 405nm are used as light sources. The use of two light sources with different wavelengths makes it possible to measure the entire particle size distribution of the sample in only one measurement channel, wherein the measurement is carried out as a wet measurement. For this purpose, an aqueous dispersion of 0.1 to 0.5% of filler is prepared and its scattered light is measured in a flow-through cell. The particle size and the particle size distribution were calculated by means of scattered light analysis according to the Mie's theory of DIN/ISO 13320.

Particle sizes of less than 0.1 μm are preferably determined by Dynamic Light Scattering (DLS). The measurement of the particle size from 5nm to 0.1 μ M is preferably carried out by Dynamic Light Scattering (DLS) of the aqueous particle dispersion, preferably using a Malvern Zetasizer Nano ZS (M alvern Instruments, malvern UK) with a He-Ne laser having a wavelength of 633nm at a scattering angle of 90 ℃.

Particle sizes of less than 0.1 μm may also be determined by SEM or TEM spectroscopy. Transmission Electron Microscopy (TEM) is preferably carried out with a Philips CM30 TEM at an acceleration voltage of 300 kV. For preparing the samples, droplets of the particle dispersion are applied to the carbon-coated

Thick copper grid (mesh size 300) and then the solvent was evaporated.

Light scattering decreases with decreasing particle size, but the smaller particle size fillers have a greater thickening effect. The fillers are classified into macro-fillers and micro-fillers according to their particle size, wherein fillers having an average particle size of 0.2 to 10 μm are referred to as macro-fillers, and fillers having an average particle size of about 5 to 100nm are referred to as micro-fillers. The macrocapsule is obtained, for example, by grinding, for example, quartz, radiopaque glass, borosilicate or ceramic, and is usually composed of chip parts. Microfillers such as mixed oxides can be prepared, for example, by hydrolytic co-condensation of metal alkoxides.

In order to improve the bonding between the filler particles and the crosslinked polymeric matrix, the filler is preferably surface-modified, particularly preferably by silanization, very particularly preferably by free-radically polymerizable silanes, in particular using 3-methacryloxypropyltrimethoxysilane. For surface modification of non-silicate fillers, e.g. ZrO ₂ Or TiO ₂ Functionalized acidic phosphates such as 10-methacryloxydecyl dihydrogen phosphate may also be used.

Furthermore, the compositions according to the invention may comprise one or more further additives, preferably stabilizers, colorants, microbicidally active ingredients, fluoride ion-releasing additives, foaming agents, optical brighteners, plasticizers and/or UV absorbers.

The compositions according to the invention preferably comprise

(a) 0.01 to 5.0% by weight, preferably 0.05 to 4.0% by weight, particularly preferably 0.1 to 3.0% by weight, of hydroperoxide, preferably CHP,

(b) 0.001 to 3.0% by weight, preferably 0.005 to 2.0% by weight, particularly preferably 0.005 to 0.50% by weight, of a peroxide, preferably DBPO,

(c) From 0.001 to 5.0% by weight, preferably from 0.003 to 4.0% by weight, particularly preferably from 0.005 to 3.0% by weight, of thiourea and/or thiourea derivatives,

(d) 5 to 95% by weight, preferably 10 to 95% by weight, particularly preferably 10 to 90% by weight, of free-radically polymerizable monomers,

(e) 0 to 85% by weight of a filler, and

(f) 0.01 to 5% by weight, preferably 0.1 to 3% by weight, particularly preferably 0.1 to 2% by weight, of additives.

All amounts herein are relative to the total mass of the composition, unless otherwise specified.

The filling level is adapted to the intended use of the material. Preferably, the filler content of the filled composite is from 50 to 85% by weight, particularly preferably from 70 to 80% by weight, and the filler content of the dental cement is from 10 to 70% by weight, particularly preferably from 60 to 70% by weight.

Those compositions consisting of said substances are particularly preferred. Furthermore, those compositions are preferred in which the individual components are in each case selected from the abovementioned preferred and particularly preferred substances. In each case, it is possible to use in each case a single component or a mixture of several components, and thus it is possible to use, for example, a mixture of monomers.

The compositions according to the invention are particularly suitable for use as dental materials, in particular dental cements, filling composites and finishing materials, and materials for the manufacture of prostheses, artificial teeth, inlays, onlays, crowns and bridges. The composition is primarily suitable for intraoral application by a dentist to repair damaged teeth, i.e. for therapeutic applications, for example as dental cement, filling composites and finishing materials. However, they can also be used non-therapeutically (extraorally), for example, for the manufacture or repair of dental prostheses such as prostheses, artificial teeth, inlays, onlays, crowns, bridges and the like.

Furthermore, the composition according to the invention is suitable for the production of shaped bodies for dental use, but also for non-dental purposes, which can be produced, for example, by casting, die casting, in particular by additive processes such as 3D printing.

Detailed Description

The invention is illustrated in more detail below with reference to examples of embodiments:

examples

Example 1

Chemically curable cements based on CHP, ATU and DBPO

The Base slurries Base-1 and Cat-5 listed in Table 1 were prepared by mixing dimethacrylate UDMA (addition product of 2-hydroxyethyl methacrylate and 2,2,4-trimethylhexamethylene-1,6-diisocyanate), V-380 (addition product of a mixture of 0.7mol of 2-hydroxyethyl methacrylate and 0.3mol of 2-hydroxypropyl methacrylate with 1mol of α, α, α ', α' -tetramethylm-xylene diisocyanate), D3MA (1,10-decanediol dimethacrylate), GDMA (glycerol 1,3-dimethacrylate) and monofunctional monomers CMP-1E (p-cumylphenoxyglycol methacrylate) and MDP (10-methacryloyloxydecyl dihydrogen phosphate) as well as stabilizer BHT (2,6-di-tert-butyl-4-methylphenol), initiator components CHP (cumene hydroperoxide 80%), DBPO (dibenzoyl peroxide, 50%) and ATU (acetylthiourea).

Table 1: composition of catalyst slurries Cat-1 to Cat-5 and Base slurry Base-1 (figures in weight%)

Components	Cat-1 ^*)	Cat-2	Cat-3	Cat-4	Cat-5	Base-1
							UDMA	21.15	21.15	21.15	21.15	21.15	24.60
V-380	16.92	16.92	16.92	16.92	16.92	19.68
							GDMA	16.92	16.92	16.92	16.92	16.92	19.68
D3MA	12.69	12.69	12.69	12.69	12.69	14.76
							CMP-1E	16.92	16.92	16.92	16.92	16.92	19.68
MDP	11.00	11.00	11.00	11.00	11.00	-
							BHT	0.10	0.10	0.10	0.10	0.10	0.10
CHP(80％)	4.30	4.218	4.131	4.046	3.873	-
							DBPO(50％)	-	0.086	0.173	0.258	0.431	-
ATU	-	-	-	-	-	1.50

^*) Comparative examples

In each case, the catalyst slurry was blended with the base slurry at a volume ratio of 1:1 and the processing time and cure time of the cements H-1 to H-5 obtained were determined. The Processing Time (PT) is determined according to the EN ISO-4049 standard (dentistry-polymer based filling, repair and adhesive materials). For this purpose, the slurries were introduced immediately after mixing into the test tubes of an exothermic apparatus with a thermocouple (type K thermocouple (Thermocoax FKI 10/50 NN); manufacturer: THERMOCONTROL GmbH, dietikon/Switzerland), with the time measurement starting from the start of mixing. The onset of cure is related to the temperature increase, which is represented by the exotherm of the exothermic device. The time point of the temperature rise corresponds to the beginning of the curing reaction and thus to the end of the processing time. The processing time is the time period from the start of mixing to the start of curing. The temperature profile of the curing reaction shows a maximum. The maximum time corresponds to the curing time. The results are shown in Table 2.

Table 2: working time (PT) and Curing Time (CT) (figures in seconds) of cements H-1 to H-5

	H-1 ^*)	H-2	H-3	H-4	H-5
						PT	143	102	72	42	29
CT	235	178	155	108	79

^*) Comparative examples

The results demonstrate that the addition of a small amount of DBPO, i.e. less than 100ppm of DBPO, results in a significant acceleration of the curing of the resin.

Example 2

Chemically cured composite cement based on CHP, ATU and DBPO

By mixing the catalyst pastes Cat-1 and Cat-3 and the Base paste Base-1 described in example 1 with the filler YbF ₃ (ytterbium fluoride) and Spherosil SiO ₂ -ZrO ₂ sil ₂ -ZrO ₂ Mixed oxide, transparent material) were mixed to prepare filler-containing catalyst slurries Cat-6 and Cat-7 and filler-containing Base slurry Base-2 having the compositions listed in table 3.

Table 3: composition of catalyst slurries Cat-6, cat-7 and Base slurry Base-2 (figures in weight%)

Components	Cat-6	Cat-7	Base-2
				UDMA	7.93	7.93	9.23
V-380	6.34	6.34	7.38
				GDMA	6.34	6.34	7.38
D3MA	4.76	4.76	5.53
				CMP-1E	6.35	6.35	7.38
MDP	4.13	4.13	-
				BHT	0.04	0.04	0.04
CHP(80％)	4.30	1.559	-
				DBPO(50％)	-	0.065	-
ATU	-	-	0.56
				YbF ₃ ¹⁾	20	20	20
Spherosil ²⁾	42.50	42.50	42.50

¹⁾ Average particle size: 250nm

²⁾ Silanized SiO ₂ -ZrO ₂ Mixed oxides (transparent materials), primary particle size d ₅₀ =60-80nm, average particle size less than or equal to 6 μm

In each case, two catalyst slurries were blended with the Base slurry Base-2 at a volume ratio of 1:1 and the processing and cure times of the resulting composite cements C-1 and C-2 were determined by oscillatory rheometry (table 4). The change in consistency of the cement during processing and curing is continuously recorded, wherein the change in consistency is detected by means of induced currents. Data recording was performed using an Agilent 34970a data recorder. For the measurement, the material to be tested is placed at room temperature (23.0. + -. 2.0 ℃ C.) beforehand. During the measurement, the lower rheometer head was brought to a temperature of 28.7 ± 0.2 ℃, which resulted in an actual measured temperature of about 28-30 ℃. This temperature corresponds to the temperature that exists under conditions in the oral cavity, such as during cementation of a dental restoration. Recording of data is started at the start of mixing.

TABLE 4 Processing Time (PT) and Curing Time (CT) (figures in seconds) for Compound cements C-1 and C-2

	C-1 ^*)	C-2
			PT	135	98
CT	177	130

^*) Comparative examples

The results demonstrate that the addition of a small amount of DBPO results in a significant acceleration of the curing of the filled composite cement.

Claims

1. Radically polymerizable dental material comprising at least one radically polymerizable monomer and a combination of a thiourea derivative and a hydroperoxide as initiator system for the radical polymerization and not comprising an amine, characterized in that it additionally comprises at least one peroxide in an amount of 1-15 wt.%, relative to the mass of the hydroperoxide, wherein the hydroperoxide is not a peroxide within the meaning of the claims and wherein the peroxide is of the formula R '- (O-O-R') _m Wherein each of R 'and R' represents an aliphatic or aromatic hydrocarbon group or an acyl group, and m is 1 or 2;

wherein the thiourea derivative comprises acetylthiourea, allylthiourea, pyridylthiourea, phenylthiourea, hexanoylthiourea or a mixture thereof, and the hydroperoxide comprises the formula R- (OOH) _n Wherein R is an aliphatic or aromatic hydrocarbon group, and n is 1 or 2.

2. Dental material according to claim 1, comprising as hydroperoxide tert-amyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butyl hydroperoxide, tert-hexyl hydroperoxide, 2,5-dimethyl-2,5-di (hydroperoxide) hexane, diisopropylbenzene monohydroperoxide, p-xylene hydroperoxide

Alkyl hydroperoxide, p-isoPropylcumene hydroperoxide or mixtures thereof.

3. Dental material according to claim 1, comprising Cumene Hydroperoxide (CHP) as hydroperoxide.

4. Dental material according to claim 1, comprising as peroxide α, α -bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3 or mixtures thereof.

5. Dental material according to claim 1, comprising as peroxide a diacyl peroxide.

6. Dental material according to claim 1, comprising isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, m-toluoylbenzoyl peroxide or mixtures thereof as peroxide.

7. Dental material according to claim 1, comprising benzoyl peroxide (DBPO) as peroxide.

8. Dental material according to claim 1, comprising Acetylthiourea (ATU) as thiourea derivative.

9. Dental material according to any of claims 1 to 8, comprising

-0.01 to 5.0% by weight of hydroperoxide with respect to the total mass of the material,

25 to 100mol% of a thiourea derivative relative to the molar amount of hydroperoxide,

-1 to 15 wt% peroxide relative to the mass of hydroperoxide.

10. Dental material according to claim 9, comprising

-0.05 to 4.0% by weight of hydroperoxide with respect to the total mass of the material,

50 to 100mol% of a thiourea derivative relative to the molar amount of hydroperoxide,

1 to 10% by weight of peroxide relative to the mass of hydroperoxide.

11. Dental material according to claim 10, comprising

-0.1 to 3.0% by weight of hydroperoxide with respect to the total mass of the material,

-an equimolar amount of thiourea derivative relative to the molar amount of hydroperoxide,

2 to 8% by weight of peroxide relative to the mass of hydroperoxide.

12. Dental material according to any of claims 1 to 8, comprising as radically polymerizable monomer at least one monofunctional (meth) acrylate or multifunctional (meth) acrylate.

13. Dental material according to claim 12, comprising as radically polymerizable monomer at least one dimethacrylate or a mixture of monomethacrylate and dimethacrylate.

14. Dental material according to claim 12, comprising as radically polymerizable monomers a mixture of methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate or isobornyl (meth) acrylate, p-cumylphenoxyethylene glycol methacrylate, 2- (2-diphenoxy) ethyl methacrylate, bisphenol A dimethacrylate, bis-GMA, ethoxylated or propoxylated bisphenol A dimethacrylate, 2- [4- (2-methacryloyloxyethoxyethoxy) phenyl ] -2- [4- (2-methacryloyloxyethoxy) phenyl ] propane), 2,2-bis [4- (2-methacryloyloxypropoxy) phenyl ] propane, the addition product of 2-hydroxyethyl methacrylate with 2,2,4-trimethylhexamethylene-1,6-diisocyanate, 0.7mol of 2-hydroxyethyl methacrylate and 0.3mol of 2-hydroxypropyl methacrylate with 1mol of α -hydroxy-propyl methacrylate, addition products of alpha, alpha' -tetramethylmetaxylene diisocyanate, di-, tri-or tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, glycerol dimethacrylate and glycerol trimethacrylate, 1,4-butanediol dimethacrylate, 1,10-decanediol dimethacrylate, mixtures thereof, and mixtures thereof, bis (methacryloxymethyl) tricyclo- [5.2.1.02,6] decane, polyethylene glycol dimethacrylate or polypropylene glycol dimethacrylate, polyethylene glycol 200 dimethacrylate, polyethylene glycol 400 dimethacrylate, 1,12-dodecanediol dimethacrylate, or mixtures thereof.

15. Dental material according to claim 12, additionally comprising at least one free-radically polymerizable monomer comprising an acid group.

16. Dental material according to claim 15, wherein the free-radically polymerizable monomer containing acid groups is a polymerizable carboxylic acid, phosphonic acid, a polymerizable phosphate or anhydrides of these substances.

17. Dental material according to any of claims 1 to 8, additionally comprising at least one organic or inorganic filler.

18. Dental material according to claim 17, wherein the inorganic filler is an oxide.

19. Dental material according to claim 18, wherein the oxide is SiO ₂ 、ZrO ₂ And TiO ₂ Or SiO ₂ 、ZrO ₂ ZnO and/or TiO ₂ Mixed oxides of (4).

20. Dental material according to claim 17, wherein the organic or inorganic filler is a nanoparticle.

21. Dental material according to claim 17, wherein the organic or inorganic filler is an ultrafine filler.

22. Dental material according to claim 17, wherein the inorganic filler is fumed silica or precipitated silica.

23. Dental material according to claim 17, wherein the inorganic filler is a glass frit or a glass ceramic.

24. A dental material according to claim 23 wherein the glass frit is quartz.

25. Dental material according to claim 17, wherein the inorganic filler is a radiopaque glass frit.

26. A dental material according to claim 25 wherein the radiopaque glass powder is a barium or strontium aluminosilicate glass powder.

27. Dental material according to claim 17, wherein the inorganic filler is a radiopaque filler.

28. Dental material according to claim 27, wherein the radiopaque filler is ytterbium trifluoride, tantalum (V) oxide, barium sulphate, siO ₂ Mixed oxides with ytterbium (III) oxide or tantalum (V) oxide.

29. Dental material according to claim 17, wherein the organic or inorganic filler is a ground prepolymer or a pearl polymer.

30. Dental material according to any of claims 1 to 8, comprising

(a) 0.01 to 5.0 wt% of a hydroperoxide,

(b) 0.001 to 0.75 wt% of a peroxide,

(c) 0.001 to 5.0% by weight of a thiourea derivative,

(d) 5 to 95% by weight of a free-radically polymerizable monomer,

(e) 0 to 85% by weight of a filler, and

(f) 0.01 to 5% by weight of additives,

in each case relative to the total mass of the material.

31. Dental material according to claim 30, comprising

(a) 0.05 to 4.0 wt% of a hydroperoxide,

(b) 0.005 to 0.60% by weight of a peroxide,

(c) 0.003 to 4.0% by weight of a thiourea derivative,

(d) From 10 to 95% by weight of a free-radically polymerizable monomer, and

(f) 0.1 to 3% by weight of additives.

32. Dental material according to claim 31, comprising

(a) 0.1 to 3.0 wt.% of a hydroperoxide,

(b) 0.005 to 0.45 wt.% of a peroxide,

(c) 0.005 to 3.0% by weight of a thiourea derivative,

(d) 10 to 90% by weight of a radically polymerizable monomer, and

(f) 0.1 to 2% by weight of additives.

33. Dental material according to claim 30, wherein the hydroperoxide is cumene hydroperoxide.

34. A dental material according to claim 30 wherein the peroxide is benzoyl peroxide.

35. Dental material according to claim 30, comprising from 50 to 85% by weight or from 10 to 70% by weight of filler.

36. Dental material according to any of claims 1 to 8 for use in therapy.

37. Dental material according to claim 36, wherein the dental material is used in therapeutic applications as a dental cement, filling composite or finishing material.

38. Non-therapeutic use of a dental material according to any of claims 1 to 37 for the manufacture or restoration of a dental restoration.

39. Use according to claim 38, wherein the dental restoration is a prosthesis, an artificial tooth, an inlay, an onlay, a crown, a bridge or a complete denture.